Altitude training (AKA hypoxic training) has been used by athletes for several decades and has recently been gaining popularity. Its popularity surged in the 1960s and ‘70s when athletes and coaches started exploring its impact in preparation for the first high-altitude Olympic Games.
In fact, the impact of altitude on performance was not well known until the 1968 Mexico City Olympic Games, where two major impacts were observed:
- Short events got faster (due to lower resistive forces), and
- Long events got slower (due to lower oxygen availability).
At an elevation of around 2,240 meters (7,350 feet), Mexico City’s high altitude was expected to impact the performance of athletes not accustomed to such conditions. Many athletes and teams arrived weeks in advance to acclimate and train at altitude, hoping to gain an advantage. This event brought attention to the potential benefits of altitude training.
Since then, altitude training has continued to evolve, and various methods have been developed to simulate high-altitude conditions, including altitude chambers, tents, and masks. These advancements have made altitude training more accessible to a broader range of athletes, not just those who are able to train in high-altitude locations.
It’s worth noting that altitude training is still a topic of ongoing research, and the optimal protocols and benefits vary among individuals and sports. Altitude training looks different for everyone, but there are some well-known pillars of successful altitude preparation. But first, how can altitude training improve your performance?
Why Train at Altitude?
Understanding how the process works on a mechanical level will help you prepare for altitude. During altitude adaptation, your body undergoes several physiological changes in response to the reduced availability of oxygen. Ideally, these adaptations optimize oxygen delivery to tissues while maintaining cellular function. Because your body still requires the same amount of oxygen, it must become more efficient since there is less oxygen available.
The benefits of altitude training include:
1. Increased Red Blood Cell Production
The primary response to altitude is an increase in erythropoiesis, which is the production of red blood cells (RBCs) in the bone marrow. Increased erythropoiesis leads to an increase in RBC mass, enhancing the oxygen-carrying capacity of the blood. Hypoxia stimulates the production of erythropoietin (EPO), a hormone that promotes the proliferation and maturation of red blood cell precursors.
Artificial EPO is banned by the World Anti-Doping Agency (WADA) due to its performance-enhancing effect and safety concerns. Training at altitude is essentially a way to increase EPO naturally.
2. Enhanced Oxygen Extraction
The oxygen dissociation curve is a graphical representation that shows how hemoglobin, a protein in red blood cells, releases and picks up oxygen depending on the oxygen levels in the blood. At high altitudes, there is a shift in the oxygen dissociation curve, facilitating enhanced oxygen unloading in the tissues. This occurs due to increased levels of 2,3-diphosphoglycerate (2,3-DPG), a molecule that decreases hemoglobin’s affinity for oxygen, allowing it to be released more readily to the tissues.
3. Increased Capillarization
Your body responds to altitude by increasing the density of capillaries in the muscles and other tissues. This process, known as capillarization, improves oxygen diffusion and facilitates the delivery of oxygen to the working muscles, enhancing your aerobic capacity.
4. Ventilatory Adjustments
Initially, there is a rapid increase in ventilation (breathing rate) and tidal volume (amount of air inhaled and exhaled per breath) in response to hypoxia. Over time, the body adapts to altitude by increasing the sensitivity of the respiratory centers in the brain, leading to a higher ventilatory response even at rest. This helps maintain appropriate oxygen levels in your blood. This adaptation can also be an indication of acclimation.
5. Increased Myoglobin Production
Myoglobin, a protein that binds oxygen in muscle cells, is upregulated in response to chronic hypoxia (low levels of oxygen). Studies have found that this adaptation improves oxygen transport within the muscles, enhancing their endurance capacity.
How to Maximize Your Training at Altitude
These physiological changes collectively enhance your body’s ability to adapt and function under low-oxygen conditions. Keep in mind that the extent and rate of these adaptations vary among individuals and depend on factors such as genetic predisposition, training status, and duration of altitude exposure. To maximize such adaptations, there are steps you can take.
Monitor & Assess
Regularly monitor physiological markers, such as oxygen saturation, resting heart rate, and HRV to track progress and make adjustments as needed. Start tracking these metrics in advance of your altitude stint so you have some context for altitude measurements.
Prioritize Sleep and Recovery
Quality sleep and recovery are a must during altitude training. Sleeping at altitude can be challenging, so creating a conducive sleep environment and practicing good sleep hygiene is paramount.
Tip: Check out this article to improve your sleep quality: 4 Ways to Get Better Sleep for Optimal Performance Recovery
Fuel & Hydrate Well
Pay extra attention to your nutrition and hydration during altitude training. Ensure you are adequately fueling your body with nutrient-rich foods and staying properly hydrated to support physiological adaptations. Some studies suggest that increasing carbohydrate intake at altitude can aid your recovery. Consider increasing the amount of electrolytes and carbohydrates you consume during training, too.
A study published in the Journal of Sports Science Medicine suggests taking an iron supplement coupled with Vitamin C is a good idea, as your body’s need for iron increases at altitude.
Adjust Intensity & Volume
Adjust the intensity and volume of your training sessions at altitude to strike a balance between challenging your body and allowing for sufficient recovery. Particular care must be taken on training intensity in both hard and easy sessions. Lower intensities are safer. It often makes sense to reduce intensity at altitude in favor of higher volumes.
Stay for Long Enough
You need to spend an adequate amount of time at altitude for physiological adaptations to occur. Research shows a minimum stay of three weeks is recommended for optimal results. Altitude training requires long stays away. If an athlete is going to commit to this, it’s important they have what’s necessary to make them comfortable (for me, it’s my coffee machine).
Was Your Altitude Stint a Success?
Did your altitude training actually work? As a coach, I assess an athlete’s hemoglobin mass with a blood test, their first lactate threshold, and their maximum aerobic power or speed (MAP or MAS). This consists of two days of testing on either side of altitude, but an approach that’s not so scientific will also work. For example, race results are a great indicator of success – if you go faster, altitude training probably helped.
I like to build an athlete dashboard and export some data from TrainingPeaks to monitor the effect of altitude and the health of an athlete in as close to real-time as humanly possible. If you’d like more information on this, feel free to get in touch via the email in the author bio.
Remember, altitude training is complex, and individual responses can vary. Working with a qualified coach or sports scientist who specializes in some aspect of altitude training can provide personalized guidance and ensure you optimize your training program for the best results.
For a more in-depth explanation behind the science of altitude training, give this video a watch:
References
Katayama, K., et al. (2010, July). Substrate utilization during exercise and recovery at moderate altitude. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S002604950900448X
Lenfant, C., et al. (1968, December 1). Effect of altitude on oxygen binding by hemoglobin and on organic phosphate levels. Retrieved from https://www.jci.org/articles/view/105948
Moore, L., et al. (2004, July 6). Analysis of the Myoglobin Gene in Tibetans Living at High Altitude. Retrieved from https://www.liebertpub.com/doi/abs/10.1089/152702902753639531
Otten, E. (2003, October). High altitude: an exploration of human adaptation. Retrieved from https://www.jem-journal.com/article/S0736-4679(03)00209-9/fulltext
Płoszczyca, K., et al. (2018, April 11). The Effects of Altitude Training on Erythropoietic Response and Hematological Variables in Adult Athletes: A Narrative Review. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5904371/
